1. Field of the Invention
The present invention relates generally to electronic devices, and more particularly to systems and methods for sensing the temperature of devices such as integrated circuits which have multiple, duplicate functional blocks.
2. Related Art
Integrated circuits such as microprocessors are becoming increasingly complex. The circuit components (e.g., transistors, diodes, resistors and the like) that form these devices are, at the same time, becoming increasingly small so that more and more functions may be performed by a particular integrated circuit. As the number of circuit components and functions grows, the amount of power that is typically consumed by these integrated circuits typically also increases. With the increased power consumption of the circuits, the amount of heat generated within the circuits increases as well. This heat may affect the performance of the devices, and may even cause the devices to fail.
As a result of the dangers presented by the generation of increased amounts of heat in electronic devices, it is often necessary to be able to detect temperatures within these devices. Thermal sensing circuits are therefore incorporated into some devices in order to detect dangerously high temperatures or even measure temperatures within the devices. For example, a thermal sensing circuit can be incorporated into an integrated circuit in order to sense the temperature of the circuit and determine whether the temperature exceeds a predetermined threshold. If the temperature exceeds this threshold, corrective action (e.g., reducing the activity within the circuit or even shutting down the circuit) can be taken in order to reduce the temperature to a safer level.
Conventionally, thermal sensors include an on-chip component, such as a thermally sensitive diode, and an off-chip component that includes circuitry configured to receive a measurement of some characteristic associated with the on-chip, and to generate a temperature measurement based on this measurement. In the case of the on-chip diode, the voltage drop across the diode is determined, and the temperature measurement is computed based upon this voltage drop.
There are several problems with this conventional approach for measuring the temperature of an integrated circuit. One of the problems relates to the positioning of the thermally sensitive on-chip component of the sensor in order to obtain the best temperature measurement. Because there are typically hotspots within an integrated circuit, the temperature that is measured by the thermal sensor will vary with the location of the on-chip component. If this component is placed near a hotspot, the measured temperature will be higher, and if it is placed near a less active portion of the chip, the measured temperature will be lower. The location of the on-chip component can therefore affect the actions that may be taken in response to certain temperature conditions. For example, if control circuitry is configured to shut down the integrated circuit when a temperature threshold is exceeded, the integrated circuit may be shut down sooner or later, depending upon the placement of the on-chip component.
The positioning of the on-chip component of the thermal sensor is addressed in some integrated circuits by using several different thermal sensors. The on-chip component of each thermal sensor can then be placed at a different location within the integrated circuit. The thermal sensors are placed without regard to hot spots or cool spots. The positioning of the sensors with respect to the hot spots and cool spots is essentially random. Some of the thermal sensors may therefore measure temperatures at locations which are closer to hotspots, while others may measure temperatures at locations which are more distant from hotspots. Control circuitry coupled to an integrated circuit with multiple sensors may be configured to respond, for instance, to an average of all of the sensed temperatures, or to the highest of the sensed temperatures. In either case, the control circuitry is typically configured to respond to the measured temperatures as a single stimulus, to which a single response (e.g. shutting down the entire chip) is provided. Thus, if a hotspot temperature measurement exceeds a predetermined threshold, the entire chip may be shut down. Conversely, if the temperature measurements are averaged, the chip may not be shut down, even though one of the sensors indicates that a safe temperature threshold has been exceeded.
It would therefore be desirable to provide systems and methods for positioning thermal sensors with respect to an electronic device so that the resulting temperature information is useful as separate [data points] that can be used by the control circuitry to more efficiently and effectively control the operation of the device.